This is not chemistry but immunology/biology. The HIV virus is what microbiologists/immunologists classify as an RNA virus. RNA viruses are not like DNA viruses because they use their RNA transcript to infect cells, namely helper t-cells. Helper t-cells are a type of white blood cell that the body uses in self defense against foreign invaders such as bacteria or other viruses. The RNA virus, HIV, attacks a receptor on the helper t-cell and injects its RNA and other proteins that it needs into the cell. The virus then uses a protein called reverse transcriptase to reverse engineer its DNA from RNA. A protein, called intergrase, is used by the RNA virus to inject its DNA that was reversed transcribed from RNA into the helper t-cell's DNA. Once this is complete, the virus uses the cells own machinery to make more copies of the RNA, other proteins, and a capsid, which encloses the RNA and the other proteins that new viruses need. This process continues until the cell is full of new viruses and bursts open destroying the host cell. The new viruses then attack other helper t-cells repeating the process, which continues until there are no more helper t-cells left. Since the human body needs helper t-cells to help other t-cells differentiate into specialized white blood cells, to help fight off infection from foreign invaders, this allows another foreign invader to destroy the human body resulting in death.